The deaths of Anwar al-Awlaki, Samir Khan and three senior associates were hailed by US President Barack Obama as a "major blow" to al-Qa'ida's most active affiliate since the killing of Osama bin Laden.

Reports last night said the bombmaker Ibrahim Hassan al-Asiri was also killed. If confirmed, it would mean the foreign operations of al-Qa'ida in the Arabian Peninsula (AQAP) had been wiped out.

Milestone

"This is another significant milestone in the broader effort to defeat al-Qa'ida," he said.

Awlaki "repeatedly called on individuals in the United States and around the globe to kill innocent men, women and children to advance a murderous agenda", he added.

Mr Obama said America had worked with Yemen for a long time tracking Awlaki, but declined to comment on his role in the killing of the American-born militant.

Five bodies were recovered from the site and Western officials believe al-Qa'ida's master bombmaker in the Arabian Peninsula may also have been killed. Awlaki (40) was the first American citizen targeted by his own government in the absence of criminal charges.

As a charismatic spokesman for the terrorists, who spoke fluent English, he inspired attacks against the West by inspiring "lone wolf" operators.

He was killed by a Hellfire missile fired from an unmanned drone near Khasaf, a desert town in Jawf province, 87 miles east of the capital Sana'a.